Ag/TiO2有序多孔复合薄膜的合成及其可见光光催化活性

摘要

以自组装SiO2胶体晶体为模板,采用TiCh溶胶凝胶浸渍提拉法制备了TiO2有序多孔薄膜(TIO),然后利用AgNO3液相渗透法将Ag纳米颗粒沉积在TIO上,成功制备了Ag/TiO2有序多孔复合薄膜(ATIO).通过Raman,FESEM,TEM,XPS和Uv-vis等分析手段对复合薄膜进行了表征,结果表明:Ag纳米颗粒的平均尺寸约为10 nm,而且与TiO2晶粒之间有强的相互作用.以亚甲基蓝(MB)水溶液为目标降解物,针对不同Ag/Ti相对原子浓度比的样品,考察了其低功率可见光光催化活性及循环使用性,并与Ag/TiO2无序复合薄膜(ATF)作了对比.研究发现,AgNO3前驱体溶液浓度为10 mmol/L的ATIO样品具有最高的可见光光催化活性,其光降解率是具有相同AgNOa前驱体溶液浓度ATF的3.19倍,显著增强的光催化活性来源于Ag纳米颗粒和TIO有序多孔结构的协同效应.循环降解实验证明样品具有稳定的光催化活性.%TiO2 ordered porous films (TIO) were fabricated via TiCl4 sol-gel dip-coating process using selfassembly SiO2 colloidal crystal as templates and Ag nanoparticles were achieved on the TIO by a liquid infiltration route, and Ag/TiO2 ordered porous composite films (ATIO) were obtained. The characteristics of the composite films were measured by Raman, FESEM, TEM, XPS and UV-vis. The results reveal that the average size of Ag nanoparticles is about 10 nm, and strong interaction exists between Ag nanoparticles and TiO2 nanocrystals. Visible light photocatalytic activities of samples with different Ag/Ti relative atomic concentration ratios and cycling tests were evaluated by analyzing the degradation of methylene blue (MB) in aqueous solution, and were compared with Ag/TiO2 disordered composite films (ATF). It is found that the TIO with AgNO3 concentration value 10 mmol/L in the precursor solution exhibits 3. 19 times visible light degradation rate compared with conventional Ag deposited TiO2 disordered film without the ordered porous structure. This obvious enhanced visible-light photocatalytic activity for the Ag deposited TIO sample can be attributed to the synergetic effect of Ag nanoparticles and TIO ordered porous structures. The repeated cycling tests suggest that samples show stable photocatalytic activity.